This study is designed to provide a model for examining the natural history of diseases in a clinical primary care practice setting. The proposed study has two primary objectives. The first is to develop a descriptive epidemiology of GI disorders in primary care practices (mainly family medicine). The second is to examine factors associated with medical outcomes and patient satisfaction. The descriptive epidemiology objective has three specific aims. The first is to examine GI disease distributions by sex, race, and age and determine the number of GI-related visits in primary care. The next two focus on GI patients with underlying acid-peptic conditions: 1) to describe treatment plans, including diagnostic procedures ordered and drug therapy; and 2) to describe the "natural history" of acid-peptic conditions in terms of symptom resolution, final diagnosis, and subspecialist referrals. The specific aims of the second objective are to develop an understanding of factors associated with medical outcomes and patient satisfaction with medical care. Hypotheses to be tested are: 1) poorer medical outcomes (e.g. lack of symptom resolution, complications) are related to cigarette smoking behavior, NSAID use, or underinsured status; 2) better medical outcomes (e.g., symptom resolution, no return GI visit) are related to use of H2 blockers or omeprazole; 3) higher patient satisfaction is related to use of diagnostic procedures (e.g. UGI x-rays, endoscopy), use of H2 blockers and omeprazole, and having insurance. Data will be collected from two Southern California sites of a family medicine research network. Gi visits and patients will be identified from the nearly 300,000 primary care visits annually accumulated by computerized billing systems at the sites. A sample of 600 GI patients with underlying acid-peptic conditions will be followed prospectively for six months. Data will be collected from medical charts, and by mail and telephone surveys. A broad spectrum of types of patients and organizational practices are represented by these study sites, so generalizability of results will be enhanced. This proposed study will overcome limitations of previous studies, since detailed data from multiple GI visits and several sources will be collected on GI patients with acid-peptic disorders.